<stdio.h> and <iostream.h>

This is a discussion on <stdio.h> and <iostream.h> within the A Brief History of Cprogramming.com forums, part of the Community Boards category; I have 2 questions.
1. EXE from <iostream.h> is much bigger than <stdio.h>. I wish to know which one work ...

> EXE from <iostream.h> is much bigger than <stdio.h>. I wish to know which one work faster?
Write the same program using both methods, and time it yourself. The answer is bound to be implementation specific.

> I was told that many OS produced with C++
Mmm
The core OS of Linux is in C, no idea about anything else